The soil erosion pictured here is the result of what? A. A mudslide caused by excessive rains B. The transition between geologic eras and eons C. Harvesting renewable resources at a rate lower than the sustainable yield D. Harvesting renewable resources at a rate greater than the sustainable yield
The Correct Answer and Explanation is:
Correct Answer: D. Harvesting renewable resources at a rate greater than the sustainable yield
Soil erosion, as pictured in many landscapes, commonly results from human activities that disrupt the natural balance of ecosystems. One of the primary causes is harvesting renewable resources such as timber, crops, or grass at a rate that exceeds the sustainable yield. Sustainable yield refers to the rate at which a resource can be used without depleting its ability to regenerate. When this threshold is surpassed, the land becomes vulnerable to degradation.
In agricultural systems, for example, repeated planting without proper soil conservation practices can lead to nutrient depletion. As vegetation cover is removed faster than it can regrow, the soil loses its structure and becomes exposed to wind and water. Without the roots of plants to anchor the soil, rainfall can easily wash it away, leading to gullies and loss of fertile topsoil. This process, known as erosion, reduces land productivity and can take centuries to reverse naturally.
Similarly, overgrazing by livestock removes ground cover and compacts the soil, which also accelerates erosion. When forests are cleared rapidly without replanting or proper management, rain can wash away the soil, especially on sloped terrain. All of these activities represent a situation in which the rate of harvesting or use exceeds the land’s natural ability to recover, matching the description in option D.
Option A, involving mudslides, is related to erosion but typically occurs suddenly after heavy rainfall rather than gradually through poor land management. Option B refers to long-term geological changes unrelated to modern soil erosion. Option C describes responsible resource use, which would actually prevent soil erosion.
Therefore, soil erosion in this context is best explained by option D: harvesting renewable resources at a rate greater than the sustainable yield. This unsustainable practice leads to land degradation and long-term environmental damage.
